A few days ago, the Sun unleashed a blast of subatomic particles, a massive wave of plasma that swept out into space at speeds of millions of kilometers per hour. On Monday, October 24th, that coronal mass ejection slammed into the Earth’s magnetic field, compressing it, and causing a secondary wave of particles to cascade down into Earth’s atmosphere at high speeds. These particles struck molecules in the air, ionizing them, which then glowed fiercely as electrons recombined with their parent atoms exciting the electrons in atoms, and when the electrons give up that energy the atoms glow.

In English? Tremendously bright northern lights! Check this out:

That was taken by photographer Eric Hines on the shore of Lake Michigan last night. You can see the glow reflecting in the water! Another photographer, Randy Halverson, took an amazing shot as well and said the aurorae were "insanely" bright, and on his website commented they were so bright it was hard to get them exposed correctly. Universe Today has a lot more pictures as well.

Aurorae were reported as far south as North Carolina and Arkansas! This was a big magnetic event, larger than we’ve seen in some time. It’s already dying down, but you never know: there may be some activity tonight. It never hurts to go outside and look to the north. If you don’t look, then you’re guaranteed not to see anything.

Comments (29)

Mike Empyema

The asstronaughts in ISS FUBAR are being roasted. “Man in Space” assumes a quiet sun. Sunspot 1330 – it’s a big one! – will be in direct line of Earth for the next week. One fat blast will be like living in a Homeland Severity airport radiation chamber. (Official dose is assumed whole-body volume, real dose 60 keV x-ray penetration is 2-3 cm. That is an order of magnitude whose narrow end you do not wish to stare down.)

I saw this in North Alabama! I didn’t know what I was seeing at the time. I thought there was perhaps a fire blazing somewhere. It was a beautiful, pretty bright hot pink. Weirdest thing ever. We just don’t EVAR see these here in Alabama! I’d love to see a full motion pic of the CME that caused this.

There happened to be a bank robbery in our town earlier in the evening so helicopters and police sirens caused some people to jump to the perfectly logical conclusion that YouFoes had landed and were going to take our babies and eat our brains.

For me, the most extraordinary feature of last night’s aurora was the intensity of red glow. Large parts of the sky were blood-red, more so than I’ve ever seen (and I live in the arctic, mind you). I’ve posted a couple of my photos from the event on G+: https://plus.google.com/104776366457712375581/posts/NPcsD9fE9G6

Er. I should probably at least try to say something intelligent.
Ooh, one thing I’ve been wondering for awhile – apparently the different colors are spectral emissions from various atmospheric gases being excited (or, to be pedantic, becoming de-excited). So why aren’t the colors mixed together? Why can we see individual colors at all? Are there huge areas in the upper atmosphere that are mostly devoid of nitrogen or oxygen?

I saw last night the auroras were out. I put on my shoes and coat, went outside looked up and it was cloudy. Then I said a few “colorful metaphors” which would probably get this post flagged. Better luck next time.

This was the first time we (unexpectedly) saw it at our new place just outside of Picton, ON, Canada. We saw a gorgeous, big, fat red glowy band from horizon to zenith surrounded by greyish streaks –for about half an hour around 10pm. A local photographer was up early this morning and captured some lovely greens: http://countylive.ca/blog/?p=18843

Red auroral light comes from oxygen at higher altitudes. It is a slow electron energy transition, and so can’t occur at lower altitudes where collisions between molecules occur before the transition can be made.

“So why aren’t the colors mixed together? Why can we see individual colors at all? Are there huge areas in the upper atmosphere that are mostly devoid of nitrogen or oxygen?”

Yes. The upper atmosphere doesn’t act like the lower atmosphere, and the middle is also different in some respects. The lower atmosphere deviates from ideal-gas laws far more strongly than, say, 70 miles up. Even ten miles up, there’s negligible water and poor mixing. By the altitudes that feel like space, the “air” has separated into a pretty-much-O2 layer, plus hydrogen and monatomic layers higher up. Aurora occur when outside energies are absorbed, so they’re absorbed by these upper layers first.

Judging from the orientation of the big dipper Randy’s picture looks like it was taken after 7:30am but the sun should have been up. Weird. I was out walking the dogs in a dark field about 4am in a dark field (’cause I’m that kinda dumb) in SW Missouri. I didn’t notice anything about the sky except the crispness and contrast. Maybe next CME.

I too live in the South(oops; I guess, technically, u guize are north of 36°. Still though, I have seen the northern lights 4 times in my life(50 years), and always, they have been red. Why don’t we citizens of southern states see the green? Anyone know??? Or, is it just my luck to only see red?

Pete Jackson Says:Red auroral light comes from oxygen at higher altitudes. It is a slow electron energy transition, and so can’t occur at lower altitudes where collisions between molecules occur before the transition can be made.
So a gas (like oxygen) can emit different colors depending on the electron energy level it’s excited to? Cool!

and

vince charles Says:Yes. The upper atmosphere doesn’t act like the lower atmosphere, and the middle is also different in some respects. The lower atmosphere deviates from ideal-gas laws far more strongly than, say, 70 miles up. Even ten miles up, there’s negligible water and poor mixing. By the altitudes that feel like space, the “air” has separated into a pretty-much-O2 layer, plus hydrogen and monatomic layers higher up. Aurora occur when outside energies are absorbed, so they’re absorbed by these upper layers first.

I think your doing a great job Joseph G. . .minus intelligence points for the gasm quote though

I have yet to witness colorful skies. . . still something to look forward to I suppose… hum ho. ho hum. If you step back turn your mind off and look at the pictures of aurora. . . it just does not look real! Nature is truly mind boggling!

But yes, seeing the aurora is definitely near the top of my personal bucket list. And I mean pinning down a really good time and place to see it and going – none of this “faint glow on the horizon on a really good day seen from a hotel room in the city” stuff.

@27 Joseph – and Phil: That display was brief but astonishingly INTENSE, the most brilliant and SATURATED RED and GREEN-BLUE COLOR I’ve seen in a long time…all of it happeneed at 43 degrees North latitude (near enough within your scope Phil) and we saw it only because we here frequently check out the sky, even if it’s lousy, and this happened right at dusk. Joseph, the sky was so bright you could easily read by it – I estimate the total light at its peak roughly equivalent to ten full moons.